Root Fungus Control Challenge Quiz

Explore common root fungal diseases in horticulture and practical strategies for their control. This quiz examines identification, symptoms, life cycles, and management options vital for healthy crops.

1. Identifying Root Rot Pathogens

   A tomato grower notices wilting and brown, mushy roots in their plants after unusually wet weather. Which fungal group is most commonly responsible for this type of root rot in horticultural crops?

   1. Phytophthora
   2. Penicillium
   3. Aspergillus
   4. Armillaria

   Explanation: Phytophthora species are notorious for causing root rot in many horticultural crops, particularly under wet conditions. Aspergillus and Penicillium are more often associated with storage or seed damage rather than root rot. Armillaria causes root diseases mainly in trees but is less common in annual crops like tomato.

2. Symptoms of Fusarium Wilt

   Which symptom most reliably distinguishes Fusarium oxysporum root infection from other root diseases in lettuce?

   1. Sudden leaf drop without wilting
   2. Yellowing of older leaves and vascular discoloration
   3. Surface white mold growth at soil line
   4. Leaf spots with purple halos

   Explanation: Fusarium oxysporum typically causes yellowing of older leaves and a brown discoloration in the vascular tissue, visible when stems are split. Leaf spots with purple halos and surface mold are not typical of Fusarium wilt, and sudden leaf drop without wilting is more indicative of other stressors.

3. Fungal Disease Life Cycle

   Which cultural practice most effectively helps break the life cycle of soil-borne root fungi like Rhizoctonia solani?

   1. Continuous monoculture planting
   2. Crop rotation with non-host plants
   3. Frequent overhead irrigation
   4. Applying high-nitrogen fertilizer

   Explanation: Crop rotation with non-host plants reduces the buildup of pathogens like Rhizoctonia in the soil. Frequent overhead irrigation can increase disease risk, monoculture promotes pathogen persistence, and high-nitrogen fertilizer does not disrupt fungal life cycles.

4. Managing Pythium Root Rot

   For a greenhouse grower, which method is most effective in controlling Pythium root rot in hydroponically grown seedlings?

   1. Pruning lower leaves frequently
   2. Sanitizing equipment with disinfectants
   3. Spraying copper foliar sprays
   4. Applying mulch around seedlings

   Explanation: Sanitizing equipment and water systems helps prevent the spread of Pythium in hydroponic systems. Mulch and pruning have little effect on waterborne pathogens, and copper sprays target foliar diseases rather than root infections.

5. Disease-resistant Varieties

   Why are disease-resistant plant varieties considered an important tool against Verticillium dahliae in vegetable crops?

   1. They only grow in sterile soils
   2. They directly kill soil fungi via exuded toxins
   3. They require no irrigation or fertilization
   4. They limit fungal colonization of the root and vascular tissue

   Explanation: Resistant varieties possess genetic traits making it harder for Verticillium dahliae to invade or damage roots and vascular tissue. Plants do not kill fungi directly, nor do they thrive without irrigation/fertilization or grow exclusively in sterile soils.